Foamed beverages, such as espresso, cappuccino and latte can be dispensed from capsules that are placed inside a beverage machine. Pre-metered and pre-packed portions of coffee and the like for the preparation of coffee-based beverages facilitate the preparation of the beverage while ensuring that the dose-to-dose quality and strength of the beverage remains constant for the same conditions of preparations (dosage, temperature, pressure, time, etc.). It also provides more convenience to the user. The capsule usually sits in a leak-tight enclosure of a special coffee machine, and hot water is passed through the capsule under pressure. The underside of the capsule is perforated under the build-up of pressure to release the extracted liquid. Some known machines use mixing devices foaming the beverages being dispensed. These devices often feed the powdered component into the water.
U.S. patent application Publication No. US 2003/0033938 discloses a cartridge for preparation of a whipped beverage. The cartridge contains one or more beverage ingredients and is formed from materials that are impermeable to air and water. An aqueous medium is introduced into the cartridge, and the beverage is forced through a restriction hole to deliver a jet of the beverage to an expansion chamber. An air inlet incorporates air into the beverage downstream of the restriction hole to provide a plurality of bubbles to the beverage at this point.
It is desirable that in certain foods, including beverages, the foaming quality and bubble size within the foam be fairly tightly controlled, to provide high quality characteristics to the food. A device is needed to provide improved foaming conditioning.